Stockholder's Equity - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Dec. 31, 2022	[1]
Equity [Abstract]
Preferred stock dividend percentage	6.00%
Ownership percentage of PACCAR	100.00%
Accumulated other comprehensive (loss) income	$ 19.0	$ 18.4

[1] The December 31, 2022 balance sheet has been derived from audited financial statements.